Adjustable chair



May 7, 1968 F n-z ET AL 3,381,997

' ADJUSTABLE CHAIR I Filed Sept. 6, 1966 3 Sheets-Sheet l INVENTORS 5 I Eon mm 5.. Kmrz ZZMA.

dfi orney May 7, 1968 E, FR|TZ ET AL ADJUSTABLE CHAIR 5 Sheets-Sheet 2 I Filed Sept.

INVENTORS Eon/4RD AZQ W May 7, 1968 FRn-z ET AL 3,381,997

ADJUSTABLE CHAIR Filed Sept. 1966 3 Sheets-Sheet 3 INVENTORS Eawma 4-. Fmrz fl/OM03 19. Fe/ r2 United States Patent 3,381,997 ADJUSTABLE CHAIR Edward E. Fritz, 201 Fernwood Drive, and Thomas A. Fritz, 221 Fernwood Drive, both of Evansville, Ind. 47711 Filed Sept. 6, 1966, Ser. No. 577,334 3 Claims. (Cl. 297--78) ABSTRACT OF THE DISCLOSURE An adjustable chair characterized by seat and back structure synchronized in movement and an independently controlled movable foot section, where pivotal arm rests are provided which are maintained in a normal supporting position through the use of permanent magnets.

The present invention relates to an adjustable chair, and more particularly to a new and novel adjustable chair having an important usage in a dental or medical ofiice.

As is known, it is desirable to provide optimum comfort for the patient while under treatment by a dentist or physician, and, as well, to provide equipment which is readily operated by the practitioner. Moreover, the relief of patient tension is further desirable to the hygienist, and during X-ray and routine dental examinations.

In this connection, the applicants herein have provided a new and improved dental or medical chair characterized by seat and back movements synchronized for comfortable positioning of the patient, and an independently controlled movable foot section. In addition to quiet and positive operation through motor control, in one form of the invention, pivotal arm rests are prvided to permit optimum patient entry onto the chair, as well as arm support at all positions. Such pivotal arm rests are maintained in a normal supporting position through the new and novel use of permanent magnets.

The chair at hand represents an important breakthrough for patient comfort and ease in a dentists or physicians office, as well as effective assistance to the dentist, physician, or hygienist during treatment, because of its ready adjustability. The invention is adapted to serve as a motor conversion chair, and permits slim line styling for an attractive appearance.

A better understanding of the present invention will he come more apparent from the following description, taken in conjunction with the accompanying drawings, wherein FIG. 1 is a view in side elevation showing the operating mechanism of the adjustable chair in accordance with the instant invention, where the chair is in a nearly upright position, and where the overall outline of the chair is shown in phantom;

FIG. 2 is a view in vertical section, taken at line 2--2 of FIG. 1 and looking in the direction of the arrows, showing certain details of the adjusting structure;

FIG. 3 is a view in side elevation, generally similar to that of FIG. 1, but showing the seat and back portion in a reclined position, and the foot portion in a raised position;

FIG. 4 is a view in side elevation, partly in vertical section, showing the position of the seat section frame when the chair is upright;

FIG. 5 is a view in side elevation, also partly in vertical section, showing the seat section frame of FIG. 4 at its fully reclined position;

FIG. 6 is a fragmentary side view of one of the new and novel arm assemblies forming part of the invention at hand, showing the arm support thereof, when raised, in broken lines; and,

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FIG. 7 is a view in vertical section, taken at line '7-7 of FIG. 6 and looking in the direction of the arrows, showing further details of the aforesaid arm assembly.

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated devices, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Referring now to the figures, the applicants new and novel adjustable chair is conventionally supported on a base (shown in phantom) having a supporting shaft 12 extending upwardly therefrom. A fixed base mount plate 14 is typically secured to the supporting shaft 12, as by bolt means 14a, forexample (see FIGS. 4 and 5). It should be understood that the base mount plate 14 defines the plane of reference with respect to movement of the over-all adjusting structure.

As should be further evident from FIGS. 4 and 5, a main pivot member 16 is typically bolted to the base mount plate 14. The main pivot member 16 includes a cylindrical portion 15a having oppositely extending free ends which are received in bearings 26 disposed on portions of seat frame 30. In other words, the seat frame 30 pivots on the main pivot member 16, where the latter forms part of the base framework together with the supporting shaft 12 and the base mount plate 14.

With further reference to FIGS. 4- and 5, as well as to FIG. 2, bearings 22 are disposed on the forward portion of the base plate 14, i.e. along opposite side edges thereof, and receive a rotatable shaft 23, the free ends of which each position a fixed pivot arm 25 having a laterally extending slide portion 27. Each slide portion 27 is adapted to move along a raceway 32 defined by a. bottom surface 38a forming part of the seat frame 34), and members 32a and a top member 32b.

Movement of the slide portions 27 in the raceways 32 stabilizes the seat frame 39 so that it remains level, without any wobbling. In this connection, FIG. 4 shows the seat frame 30 in its normal position, i.e. with the chair upright, while FIG. 5 shows the seat frame 34 in a fully reclined position, where, between such end positions, the slide portion 27 moves from one end of the raceway 32 (FIG. 4) to the other end of the raceway 32 (FIG. 5).

It should be understood that the seat frame 30 may be assembled in various manners, but, by way of illustration, the seat frame 30 herein is defined by an arrangement of lengths of angle iron welded together, where an area is provided, as shown in FIG. 2, for the base mount plate 14. In any event, it is not believed necessary to further describe in detail the seat frame 30, nor the conventional arrangement by which the pillow or cushion is mounted thereon.

:With reference now to FIGS. 1, 2 and 3, it will be noted that the forward portion of seat frame 30 includes upstanding ears or hinge points 3% to which the foot frame 50 is pivotally mounted, while the rear portion of the seat frame 38 includes upstanding ears or hinge points 3% to which, in this instance, the back frame 70 is secured. In other words, and as will become apparent herebelow the foot frame 5% is pivotal with respect to the seat frame 30 and independently of any synchronized movement between the seat frame 30 and the back frame 7! The preceding relationship is accomplished by means of control arrangeemnts 45 and 55, where the control arrangement 45, i.e. the control for the synchronized movement of the scat frame 3i} and the back frame 70, will be first discussed. A power source in the form of an electric motor 46 is mounted on the seat frame 30 and, hence, is movable therewith. The motor 46 operates a rotatable screw 47, where the free end of the latter is supported on a member 39d depending from the seat frame 30. As should be particularly understandable from FIGS. 1 and 2, a transfer member 49 is movable along the rotatable screw 47 upon energization of the motor 46.

The transfer member 49 typically comprises an internally threaded cylindrical member 4% having a connecting member 49b secured thereto by pivot pins 49c (see REG. 2). In otherwords, the connecting member 4912 is pivotal with respect to the cylindrical member 4% depending upon the position of the transfer member 49 along the rotatable screw member 47.

An interconnecting arm 71 is fixedly secured to the transfer member 49, passing rearwardly to a pivot point 76a to which a central rib 70b of the rear frame 70 is connected. In other words, as the transfer member 49 travels along the threaded screw member 47, the interconnecting arm 71 moves along therewith, causing the pivoting of the back frame 70 at pivot point 79a disposed at the middle thereof.

In order to synchronize the movement of the seat frame 36 and the back frame 70, a cam 75 is provided, the latter being secured to a member 76 extending from the base mount plate 14 (see FIG. 2). An intermediate member '77 is disposed on the transfer member 49 oppositely from the interconnecting arm 71, and a fixed extending pin 77a with a roller 77b is secured thereto. The aforesaid cam 75 has a camway 75a disposed therein, which camway 75a typically extends, from back to front of the chair, forwardly, then upwardly, and then up wardly at a lesser angle of inclination, to achieve the desired synchronization between the seat frame 30 and the back frame 7 With further reference to FIG. 2, the extending pin 77a has one portion of which moving through a passageway 39c defined by member g of the seat frame 39, and another portion of which moving through a passageway 3th defined by member 3011 of the seat frame 30. In other words, and by way of example, when the roller 77b of the extending pin 77a passes forwardly along the portion of the camway 75a proximate the back of the seat frame 30, the portions of the extending pin 77a in the passageway 30c and 33f effect no movement of the seat frame 30. However, and by way of further example, when the roller 77b moves forwardly and upwardly in the camway 75a in the cam 75, the seat frame 36 tilts.

In other words, the preceding overall structure represents a cam and a cam follower, where the follower effects the desired action of synchronizing the position of the seat frame 30 with respect to the back frame 76. All of such action occurs, of course, when the motor 46 is energized, causing the transfer member 49 to move along the threaded screw member 47. Restated otherwise, not only is the rear frame 74) pivoting at point 78a, but the seat frame 30 is tilting, depending upon the position of the roller 79b along the camway 75a in cam 75.

Independently of the preceding, the other control arrangement operates the functioning of the foot frame 50. In this respect, and excepting the discussed cam 75, the control arangement 55 is very similar to the control arrangement 45. More specifically, a power source in the form of an electric motor 56 is provided, where the latter operates a threaded screw member 57. A depending member from the seat frame 30 (not shown) supports the free end of the threaded screw member 57, much like depending member 30d, and a transfer member (also not shown) serves to operate interconnecting members 81 and 82, pivotal together (see FIG. 3), where interconnecting member 82 is in pivotal relationship (not shown) with the foot frame 50.

In use, and very similar to the operation of the control arrangement 45 if the intermediate member '77 and associated cam were not present, the transfer member (not shown) moves along the threaded screw member 57 upon energization of the motor 56, causing the interconnecting member 81 to pivot with respect to interconnecting member 82, the latter moving the foot frame 50 also in a pivotal arrangement.

It should be understood from the above, therefore, that the instant invention provides for the movement of the seat frame 30 and the rear frame 70 in synchronized relationship, and for the independent movement of the foot frame 50. The preceding is accomplished in a positive manner, without undue noise, and with ease of operation through a simple foot or hand controlled electrical switching device (not shown) for energizing the respective motors 46 and 56.

As should be apparent from FIG. 1, the over-all contour of the adjustable chair is shown in phantom, includin g the fixed arm rest therefor. In this latter regard, however, the invention at hand proceeds further in providing an alternative form of arm rest (see FIGS. 6 and 7), based on generally similar support structure to that shown in FIGS. 1 to 5, inclusive.

More specifically, the applicants improved arm rest permits the movement of the arm supporting member thereof so as to allow easy entry and exit from the chair. Additionally, the arm supporting member is arranged to move with the adjustment of the chair so that the patient always has the desired arm support irrespective of the position of the rear frame 70 with respect to the seat frame 30.

With particular reference now to the aforesaid FIGS. 6 and 7, an arm supporting member 91 is pivotally mounted at 91a to a pin mounted on the rear frame assembly. Brackets 92 extend forwardly from pivot point 91 and define a pivot 94 for a member 95 which extends downwardly to a pivot 96 in upstanding car 97 disposed on the seat frame 36. A parallelogram relationship is achieved through the pivot at car 30c, pivot 91a, pivot 94, and pivot 96, meaning that the brackets 92 always mantain a parallel relationship with the seat frame 30.

In order to easily accomplish the positioning and securing of the arm supporting member 91, a magnetic means 93, in the form of a permanent magnet, is held by screws 92a between the brackets 92. As should be apparent from FIG. 7, the arm supporting member 91 is positioned through a magnetic relationship with respect to the permanent magnet 93, but, of course, is readily raised, when desired, to achieve the desired entry and exit of the patient from the chair. It might be noted that the cushioning or upholstery on the arm supporting member 91 is shown in phantom for reasons of clarity of presentation.

In view of the above, it should be understood that the applicants herein have provided a highly effective adjustable chair with particular adaptability for dental or medical office use. As stated, the rear frame and seat frame are synchronized for relative movement wit-h respect to each other, and the foot frame is independently operable. Moreover, a new and novel arm rest approach is provided, permitting arm support at all positions of the rear frame with respect to the seat frame. Additionally, the arm rest can be readily raised, as well as secured into operative position, all to the benefit of the chair user.

It should be apparent that the adjustable chair described herein is susceptible to various changes within the spirit of the invention. For example, proportioning may be varied, different securing means employed in the arm rest arrangement, the raisable portion of the latter omitted, and general changes made in structure to accommodate manufacturing procedures. Moreover, instead of the atone-discussed rotatable screw and motor arrangement, a piston operated by a hydraulic system would also be an effective power source for the desired adjustments. Therefore, the above description should be considered illustrative and not as limiting the scope of the following claims.

We claim:

1. An adjustable chair comprising a supporting framework, a seat frame pivotally mounted on said supporting framework for tilting action, a back frame pivotally mounted on said seat frame, a foot frame pivotally mounted on said seat frame and movable independently of said seat frame and said back frame, an arm rest, a cam on said supporting framework and cam follower structure on said seat frame and other structure interconnecting said back frame and said cam follower structure synchronizing relative movement between said seat frame and said back frame, power means controlling movement of said cam follower structure, and other power means controlling movement of said foot frame.

2. The adjustable chair of claim 1 where said other power means drives a screw member, where a transfer member is movable along said screw member, and where at least one other member interconnects said transfer member and said foot frame to define a pivot arrangement for said foot frame.

3. An adjustable chair comprising a supporting framework, a seat frame pivotally mounted on said supporting framework, a back frame pivotally mounted on said seat frame, a foot frame pivotally mounted on said seat frame, an arm rest, and means synchronizing relative movement between said seat frame and said back frame, said arm rest being defined by an arm supporting member pivotal with respect to said back frame and another member pivotally connected to both said arm supporting member and said seat frame, whereby said arm supporting member remains in a generally parallel relationship with respect to said seat frame, and said arm supporting member having an independently pivotal portion, and magnetic means maintaining said independently pivotal portion in an operative position.

References Cited UNITED STATES PATENTS 2,714,922 8/1955 McKibban et a1. 297-83 2,944,595 7/1960 Barabas el; al. 297- s5 3,005,660 10/1961 Winick 297 319 X 3,016,264 1/1962 Hughes 297 s5 x 3,142,509 7/1964 Ehrke et a1 297-71 X 3,191,990 6/1965 Rugg ct al 297-s3 FOREIGN PATENTS 867,076 5/1961 Great Britain.

JAMES T. McCALL, Prl'lmlry Examiner. 

